Automatic paper loading and guiding mechanism

ABSTRACT

Driven rubber belts are arranged for receiving a roll of paper. A paper deflector is positioned to catch the free end of the rotating paper roll for guiding it through a paper feeding mechanism.

[ 1 Dec. 18, 1973 AUTOMATIC PAPER LOADING AND GUIDING MECHANISM 3,558,028 1/1971 Bunting.......... 3 698 658 10/1972 Skei 12/1970 Bundschuh et a1.

[75] Inventor: Roger C. Edrinn, Loveland, C010.

' [73] Hewlett-Packard Company, Palo FOREIGN PATENTS OR APPLICATIONS Assignee:

Austria Alto, Calif.

22 Filed: Apr. 20, 1972 Appl. No.: 245,998

Primary ExaminerLeonard Christian Att0rneyR01and 1. Griffin f m 1... h um m .m .w J .m m.m fun T dm C CD. A w s R T nr S am B ec A wflpnv 58 .md m Ma n. wA vmr e m 5 .1. DD. 1 1 95 .9 6 6 2 2 1 R R M0 M 5 N05 //7 452 274% n} m B "m m mam nm m h j "mc7 m m-. ue UWSIU L W dU LdM UhF H M 555 References Cited free end of the rot atmg paper roll. for guiding it I through a paper feeding mechanism.

UNITED STATES PATENTS 3.489.361 1/1970 Marion et gal. 242/55 6 Claims, 2 Drawing Fignres PMENTEI] DEC 18 I975 igure REFERENCE TO RELATED APPLICATION DESCRIPTION OF THE PREFERRED EMBODIMENT The printer shown in FIG. 1 is symmetrical about the This application is related to a portion of the subject 5 section line AA and is of the type shown in the above matter of copending U. S. patent application Ser. no. 1,534,437 entitled IMPROVED PROGRAMMABLE CALCULATOR, filed on June 15, I97] by Robert E. Watson, Jack M. Walden, and Charles W. Near and assigned to the same assignee as the present application.

BACKGROUND AND SUMMARY OF THE INVENTION This invention relates generally to paper guiding mechanism and more particularly to an improved mechanism for automatically loading and guiding rolled paper.

Such mechanisms have been employed in various office machines-and, more recently, in printing units associated with high-speed computers and desk top calculators. Most of these units require time consuming manual threading each time a'roll of paper is inserted. It is desirable to supply a unit which automatically threads thefree end of each roll as it is inserted. Those few units inthe prior art which can automatically accommodate paper rolls are limited to one particular roll diameter. It is an advantage to be able to change paper types at .willand to be able to reinsert, for example, a partially consumed roll. In addition, prior art units have, through the use of rollers in contact with paper, employed a pushing technique for guiding and feeding the paper, which is only successful in handling the heavier weights of paper. Printers associated with computers and desk top calculators must have the ability to accommodate many different, types of paper in performing a variety of printing functions. A number of these units employ thermal means for printing characters, thus requiring the use of thermally sensitive paper which is characteristically thinner than those papers used with impact printers.

Accordingly, it is the principal object of this inven-' tionto provie an improved paper loading and guiding mechanism which will automatically thread the free end'of a roll of paper along a-desired'path.

It is a further object of this invention to provide an improved paper loading and guiding mechanism which is capable of accommodating all commonly available thicknesses of printing papers and rolls ofvarying diameter.

These objects are accomplished in accordance with the preferred embodimentof this invention by employing two driven rubber belts for receiving a roll of paper and for making contact therewith at each'edge thereof. A bucket for holding the paper roll during use is located above the belts. A paper guide and deflector member is positioned so as to be in contact with a front portion of each of the belts and so that an end portion of the deflector member protrudes into the bucket cavity for deflecting the free end of the roll into position for being guided by the belts.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a printing unit which embodys the'present invention."

FIG. 2 is a sectional view taken along the line AA in FIG. 1 to show the relationship of the paper, belts, and paper guide and deflector member.

' away from the bucket area.

mentioned copending patent application. Paper roll 12 is loaded into the printer by lifting bucket cover 13 and placing the roll in position for uprolling' forward from the bottom. This bucket cover serves to keep the free end of the paper within bucket halves 3 and 8 during loading and, after loading, to prevent the free end from reloadingfitself through the mechanism. A belt 9 is provided at each edge of the paper and is driven by drive pulley 5 which is in turn driven by motor 11. A print head 1 is spring loaded against a driven platen 2 and is cammed away therefrom at the appropriate time during loading by a head lifter 4 to facilitate passage of the free end of the paper roll. The diameter and speed of the platen are such that its surface speed'is approximately '5 percent faster than that of. belts 9 to insure that the paper is maintained under tension after loading is completed. Drive pulley 5 and an associated rear idler pulley 10 are crowned so that the belts will be selfcentering. An associated front idler pulley 7 is flat and is provided to maintain the lower portion of the belt The weight of the paper stretches rubber belts 9, allowing the paper to roll forward until it rests against a paper guide 6. A downhill slope toward the paper guide is created by the placement of rear idler pulley 10. With the paper roll in this position and the belts moving, the free end of the paper is constrained by the belts 9, paper guide 6, and roll 12 to travel below the paper guide and between it and the belts. FIG. 2 illustrates a section through the paper guide showing the relative positions of the paper, belts, and paper guide. The paper is edge-guided through the mechanism during loading and subsequent operation. Ordinarily, paper does not lend itself to successful edge guiding due to its very low compressive strength. The present invention overcomes that'problem by providing paper guide-6 with" a convex bottom surface against'which the paper is held by belts 9, under tension, thus preventing buckling of the paper. Y Y

In selecting materials for various parts of the loading mechanism it is important to maintain compatible coefficients of friction. The coefficient of friction between the paper and paper guide 6 should be low relative to that existing between the paper and belts in order that the belts can drive the paper through the mechanism. Similarly, the coefficient of friction between the paper and platen 2 should be high relative to that existing between print head 1 and the paper in order that the paper may be driven through the mechanism during printing. In addition, the drag introduced by the belts and paper guide due to the paper moving faster than the belts during printing must not be so great as to tear the paper or overload the motor.

I claim:

-l. A mechanism for automatically loadingand guiding paper from a roll, said mechanism comprising:

a paper holding bucket having an opening in the bota paper guide and deflector member having a deflecguide and deflector member has a convex surface for tor portion that protrudes into the cavity of the contacting the paper and belt so that the paper is bucket and a guide portion that contacts the belt strengthened by being constrained to follow a curved for constraining the paper to travel between the path. belt and the guide; and 5 5. A mechanism as in claim 2 further comprising a means for driving the belt. cover disposed over the top end of the bucket for keep- 2. A mechanism as in claim 1 wherein a pair of belts ing the free end of the paper inside the bucket during is positioned adjacent to the opening in the bottom of loading and for preventing the free end from reloading the bucket for contacting the paper roll near its edges. itself through the mechanism during subsequent opera- 3. A mechanism as in claim 1 further comprising a tion. cover disposed over the top end of the bucket for keep- 6. A mechanism as in claim 2 wherein said paper ing the free end of the paper inside the bucket during guide and deflector member has a convex surface for loading and for preventing the free end from reloading contacting the paper and belts so that the paper is itself through the mechanism during subsequent operastrengthened by being constrained to follow a curved tion. path.

4. A mechanism as in claim 1 wherein said paper UNITED STATES PATENT OFFICE CERTIFICATE OF' CORRECTION Patent No. 3 779,473 Dat d December 18, 1973 Invent fl Roger C. drinn It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 7, change 1,534,437" to read l53,437 line 15, change "mechanism" to read mechanisms v and line 42, change "provie" to read provide Signed and sealed this 9th day of April 197k.

(SEAL) Attest: v EDWARD IMPLE'ICHERQJR. c. MARSHALL DANN' Attesting Officer Commissioner of Patents uscOMM-DC GOING-P69 u.s. sovcmmem IRINJMQ Ol'flCE :10 o-su-su FORM PO-IOSO (10-69) 

1. A mechanism for automatically loading and guiding paper from a roll, said mechanism comprising: a paper holding bucket having an opening in the bottom end thereof; a belt positioned adjacent to the opening in the bottom end of the bucket for receiving a roll of paper and for frictionally controlling movement of the roll; a paper guide and deflector member having a deflector portion that protrudes into the cavity of the bucket and a guide portion that contacts the belt for constraining the paper to travel between the belt and the guide; and means for driving the belt.
 2. A mechanism as in claim 1 wherein a pair of belts is positioned adjacent to the opening in the bottom of the bucket for contacting the paper roll near its edges.
 3. A mechanism as in claim 1 further comprising a cover disposed over the top end of the bucket for keeping the free end of the paper inside the bucket during loading and for preventing the free end from reloading itself through the mechanism during subsequent operation.
 4. A mechanism as in claim 1 wherein said paper guide and deflector member has a convex surface for coNtacting the paper and belt so that the paper is strengthened by being constrained to follow a curved path.
 5. A mechanism as in claim 2 further comprising a cover disposed over the top end of the bucket for keeping the free end of the paper inside the bucket during loading and for preventing the free end from reloading itself through the mechanism during subsequent operation.
 6. A mechanism as in claim 2 wherein said paper guide and deflector member has a convex surface for contacting the paper and belts so that the paper is strengthened by being constrained to follow a curved path. 